After two years of long-term TPN, children had abnormal lymphocyte count, low levels of serum albumin and protein in-group I. Four children developed selenium deficiency, and 15 children on PN for 3 yrs had significantly low Hb and Hct compared to controls. Eleven of 29 children died from low lymphocyte count. Seven died (5 from SBS, 1 from pseudoobstruction, 1 from immune deficiency), 4 from TPN induced cholesistatic liver disease and from bacterial septicemia. The gene discussed is GSTM1; the disease is selenium deficiency.